MARINE ENVIRONMENT PROTECTION MEPC 71/INF.9 … · the IMO (Nengye & Frank 2012). Hydrodynamic...

IMEPC71MEPC 71-INF-9docx

E

MARINE ENVIRONMENT PROTECTION COMMITTEE 71st session Agenda item 4

MEPC 71INF9 31 March 2017

ENGLISH ONLY

HARMFUL AQUATIC ORGANISMS IN BALLAST WATER

Information on a new technology of ballast water management systems for economical

and practical compliance with the Ballast Water Management Convention and its guidelines

Submitted by China

SUMMARY

Executive summary This document provides in the annex a new technology Inactivation of heterosigma akashiwo in Ballast Water by Conical Orifice Plate-generated Hydrodynamic Cavitation of ballast water management systems In comparison with traditional used single- and multi-hole orifice plates the use of conical-hole orifice plate yielded the highest inactivation percentage of 5112 with only 684 energy consumption (based on 50 inactivation percentage) Moreover it allowed the use of a low-pressure pump

Strategic direction 13

High-level action 1303

Output 13031

Action to be taken Paragraph 6

Related documents None

Background 1 Regulation A-2 of the International Convention for the Control and Management of Ships Ballast Water and Sediments 2004 requires that discharge of ballast water shall only be conducted through ballast water management in accordance with the provisions of the Annex to the Convention 2 Regulation D-3 of the Ballast Water Management Convention provides that ballast water management systems used to comply with this Convention must be approved by the Administration taking into account guidelines developed by the Organization

MEPC 71INF9 Page 2


3 The purpose of the Guidelines for approval of ballast water management systems (G8) is to ensure uniform and proper application of the standards contained in the Convention 4 Currently filtration electrolysis and ultraviolet irradiation are the most commonly used techniques in most ballast water management systems (BWMS) However these techniques possess some disadvantages such as high energy consumption potential risk to the receiving water body etc In comparison with the traditionally used single- and multi-hole orifice plates the conical-hole orifice plate yielded the highest inactivation percentage 5112 and consumed only 684 energy (based on a 50 inactivation percentage) Moreover it allowed the use of a low-pressure pump 5 On the basis of the above Shanghai Maritime University China conducted a series of experiments to gain a new environmentally friendly technology of BWMS with economic benefit and safety as set out in the annex Action requested of the Committee 6 The Committee is invited to note the information contained in this document

MEPC 71INF9 Annex page 1


ANNEX

NON-CONFIDENTIAL INFORMATION ON BALLAST WATER TREATMENT TECHNLOLOGY BY CONICAL ORIFICE PLATE-GENERATED HYDRODYNAMIC

CAVITATION

Table of contents 1 Introduction 2 Materials and Methods 21 Heterosigma akashiwo and Culture Medium 22 Hydrodynamic Cavitation Setup 23 Determination of Viable Microalgae Concentration 24 Calculation of the Energy Consumed Per Cubic Meter of Sea water 25 Calculation of the Amount of Microalgae Inactivated Per Joule 3 Results and Discussion 31 Heterosigma akashiwo Inactivation Using a Single-hole Orifice Plate 32 Heterosigma akashiwo Inactivation by Multi-hole Orifice Plates 33 Heterosigma akashiwo Inactivation by a Conical-hole Orifice Plate 34 Repeating Inactivation of Heterosigma akashiwo by Orifice Plate 35 Energy Consumption of Heterosigma akashiwo Inactivation by Orifice Plate-

generated Hydrodynamic Cavitation 4 Conclusions 5 References 6 Appendix A-Calculation of the Energy Consumed Per Cubic Meter of Sea water 7 Appendix B-Calculation of the Amount of Microalgae Killed Per Joule 8 Tables 9 Figures



1 Introduction According to the information updated in May 2014 by the International Maritime Organization (IMO) currently there are a total of 42 ballast water management systems which have received type approvals from their respective administrations (IMO 2014) Among them filtration electrolysis and ultraviolet irradiation are the most commonly used techniques (Tsolaki amp Diamadopoulos 2010 Werschkuna et al 2014) However all of these techniques possess some disadvantages and none of them completely meets all of the requirements for safety practicality economic benefit effectiveness and environmental friendliness as proposed by the IMO (Nengye amp Frank 2012) Hydrodynamic cavitation is generally defined as the phenomenon of nucleation growth and collapse of cavitation bubbles due to the quick drop and recovery of hydrostatic pressure (Sawant et al 2008) The collapse of cavitation bubbles generates very localized violent fluid turbulence in the form of high velocity liquid jet shock wave or other form which can be used to inactivate microorganisms in wastewater to degrade organic pollutants to extract biofuel to synthesize nanocalcite etc (Save et al 1994 Arrojo amp Benito 2008 Gogate 2007 Pal et al 2010 Sonawane et al 2010) Apparently hydrodynamic cavitation technology is environmentally friendly and the hydrodynamic cavitation setup is for the most part quite simple to operate and maintain (Gogate 2007 Wu amp Shen 2012) These advantages exhibit the potential benefits of introducing hydrodynamic cavitation to treat ballast water In this work we have designed a conical-hole orifice plate to generate hydrodynamic cavitation for inactivation of microalgae with size lt50 um in ballast water A typical red tide microalga Heterosigma akashiwo was chosen as the test microorganism The inactivation percentage and energy efficiency under different treatment conditions were determined and analyzed Moreover energy consumption between our experimental orifice plate inactivation set-up and typical commercial ballast water management system was compared The purpose of this work is to determine the efficacy of treating ballast water by orifice plate generated hydrodynamic cavitation 2 Materials and Methods 21 Heterosigma akashiwo and Culture Medium Heterosigma akashiwo was purchased from Ocean University of China Transparent rectangular glass tank and f2 medium were used to culture Heterosigma akashiwo The culture condition includes lightdark ratio 14h10h temperature 20 light intensity 4000 lux aeration rate 3 Lmin 1L culture medium containing Heterosigma akashiwo in logarithmic growth stage was diluted by 19 L artificial sea water to simulate ballast water 1 kg commercial sea salt was dissolved into 30 L distilled water to form artificial sea water 22 Hydrodynamic Cavitation Setup The inactivation of Heterosigma akashiwo was conducted using a hydrodynamic cavitation setup (Fig 1) (Gogate 2011 Patil amp Gogate 2012) An orifice plate was placed in the pipe system to induce hydrodynamic cavitation The specifications and parameters of the circular orifice plates used here are presented in Table 1 Table 2 and Fig 2 First a start-up high-pressure centrifugal pump using frequency conversion control (Y2-80M1-2 Southern Pumps Corporation China) was used to drive simulated ballast water flow through the pipe system Subsequently hydrodynamic cavitation occurred continuously when simulated ballast water passed through the orifice plate Two pressure transducers (PX409-150GUSB Omega Engineering Ohio) were placed before and after the orifice plate to determine the water pressure and temperature An electromagnetic flow meter (XKD99Z Shanghai Star Instrument Co Ltd



China) was installed in the pipe system and was used to determine the flow rate For each experiment blank control samples are taken from the location of pressure transducer 1 Inactivation percentages of blank control have been subtracted from the inactivation percentages presented in the text and figures 23 Determination of Viable Microalgae Concentration A flow cytometer (Cyflow Cube 6 Partec GmbH Muumlnster Germany) was used to accurately determine the low viable Heterosigma akashiwo concentration in simulated ballast water Guavareg ViaCountreg reagent (Guava Technologies Inc Millipore USA) was used to stain and distinguish between viable and non-viable cells nucleus-containing debris and other impurities based on the differential permeability of DNA-binding dyes in the ViaCountreg reagent The staining procedure was as follows a 10 mL water sample containing microorganisms in a 40 mL centrifuge tube was continuously agitated to maintain homogeneity of the tube contents Subsequently 400 uL homogeneous sample and 400 uL Viacountreg reagent were added into a sample tube and were well agitated After 30 min staining in the dark and storage at a temperature below 10oC the stained sample was distilled by 200 uL 02 um filtered sea water and then numerated using flow cytometry 24 Calculation of the Energy Consumed Per Cubic Meter of Sea water The energy consumed per cubic meter of sea water (specific energy consumption Ws J∙m-3) during hydrodynamic cavitation treatment was used to evaluate the energy consumption and then compared with the energy consumption of the typical commercial ballast water treatment system Appendix A describes the derivation process for calculating Ws using the following expression

3

1 2689 10 ( )sW p p

Where 1p and 2p are the pressure just before and after the orifice plate respectively PSI

25 Calculation of the Amount of Microalgae Inactivated Per Joule

The amount of microalgae inactivated per joule (AMIJ As cells∙J-1) during hydrodynamic cavitation treatment was used to evaluate energy efficiency Appendix B describes the derivation process of calculating AMIJ and the result was calculated from the following formula

2

1 2

1 2

145 10 ( )

( )s

n nA

p p

Where n1 and n2 are the concentrations of viable microalgae before and after treatment respectively expressed as cells∙mL-1

3 Results and Discussion

31 Heterosigma akashiwo Inactivation Using a Single-hole Orifice Plate For a single-hole orifice plate the impact of hole-area percentage on the inactivation effect of hydrodynamic cavitation was investigated and the results are presented in Fig3 The inactivation percentage negatively associated with the hole-area percentage and the maximal inactivation percentage of 4924 was achieved using a No3 orifice plate with 6 hole-area percentage In contrast AMIJ positively associated with hole-area percentage and the maximal AMIJ of 153times107cells∙J-1 was obtained using a No7 orifice plate with 66 hole-area percentage



In comparison the highest inactivation percentage of 82 for zooplankton using an orifice plate with 75 hole-area percentage was achieved elsewhere (Sawant et al 2008) which was much higher than that achieved here for Heterosigma akashiwo The zooplankton cell sizes were gt50um in contrast with that of 18 to 34 um for Heterosigma akashiwo (Bowers et al 2006) Thus microorganisms with small sizes appear to be more resistant to hydrodynamic cavitation while other unknown biological characteristics such as morphology physiology and behaviour may also contribute to the difference in inactivation percentage The pressure difference before and after the orifice plate (Hereinafter referred to as the pressure difference) decreased with hole-area percentage (Fig 3B) and higher pressure differences associated with higher inactivation percentages (See Fig 3) Nevertheless higher pressure differences also associated with lower energy efficiency and higher pressure requirement to the pump The viable Heterosigma akashiwo concentration before and after No3 orifice plate-generated hydrodynamic cavitation inactivation was determined using flow cytometry and a typical result is presented in Fig 4 After inactivation the concentration of viable Heterosigma akashiwo reduces 34241 cells∙mL-1 while the concentration of dead Heterosigma akashiwo and its nucleus-containing debris increases 7116 cells∙mL-1 Therefore over 792 of the inactivated Heterosigma akashiwo were broken into tiny cell debris that could not be detected by flow cytometry The results clearly indicate that Heterosigma akashiwo is inactivated by breaking it into cell debris which is most likely due to the impingement from violent fluid turbulence 32 Heterosigma akashiwo Inactivation by Multi-hole Orifice Plates Multi-hole orifice plates were also introduced to generate hydrodynamic cavitation and to inactivate Heterosigma akashiwo For multi-hole orifice plates with constant hole-number the relationships between hole-area percentage and inactivation percentage AMIJ flow rate and pressure difference were similar to that of the single-hole orifice plates (results for plates with 4 holes shown in Fig 5) The impact of the hole-number of multi-hole orifice plate on inactivation effect was also researched and the results are presented in Fig5 For orifice plates with 6 and 25 hole-area percentages the inactivation percentage and pressure difference both decreased with hole-number while AMIJ and flow rate increased with hole-number Eg For orifice plate with 6 hole-area percentage when the hole-number increased from 1 to 4 a 799 decline in inactivation percentage and a 048times105 Pa drop in pressure difference were observed On the other hand there was a 045 m3∙h-1 addition to the flow rate and an AMIJ increase of 06times105 cells∙J-1 Hence for multi-hole orifice plates the effect of increasing the hole-number was similar to that of increasing the hole-area percentage Opposite experimental result was obtained by other researcher in which an increase in hole-number obtained higher cavitational yield (Sivakumar and Pandit 2002) Theoretically for a constant hole-area percentage an exponential increase in hole-number results in an exponential increase in hole-perimeter According to previous research (Zhao amp Zhang 2008) the hole-perimeter of the orifice plate inversely affected the pressure difference and consequently was inversely proportional to the inactivation percentage The impact of hole-number on Heterosigma akashiwo inactivation was further investigated under constant pressure differences (Table 3) For No2 and 8 orifice plates an elevation of the pressure difference to 216times105 Pa was applied by changing pump frequency so that all three orifice plates could operate on the same pressure difference Nevertheless even under constant pressure difference an elevation of hole-number still causes the reduction in inactivation percentage Eg increasing hole-number from 1 to 16 decreases the inactivation



percentage by 1911 (See Table 3) In contrast using similar experimental conditions plus the adoption of almost constant flow rate an improvement in cavitation effect (as exhibited by the elevation in iodine liberation) was observed (Vichare et al 2000) 33 Heterosigma akashiwo Inactivation by a Conical-hole Orifice Plate Conical-hole orifice plate was further introduced to inactivate Heterosigma akashiwo and the results are shown in Table 4 In comparison with single- and multi-hole orifice plates the conical-hole orifice plate not only yielded equivalent inactivation percentages but also elevated the energy efficiency considerably Eg for No10 conical-hole orifice plate with 6 hole-area percentage a maximal inactivation percentage of 5112 was observed which was even slightly higher than that of the single-hole orifice plate (No3 See Fig 3A 6 hole-area percentage) Moreover due to the low pressure difference AMIJ for No10 conical-hole orifice plate reached 210times107 cells∙J-1 which was at least 635 times higher than that of the single- and multi-hole orifice plates (No3 See Fig 3A 6 hole-area percentage) The pressure before the conical-hole orifice plate was also low in comparison with that obtained before the single-hole orifice plate Eg the highest pressure before the conical-hole orifice plate was about 20times104 Pa (No10) in comparison with that of 255times105 Pa for the single-hole orifice plate (No3) Low pressure before the orifice plate is desirable since it allows the use of a low-pressure centrifugal pump to trigger the hydrodynamic cavitation Moreover it reduces the pressure-resistance requirement of the pipeline In addition different assembling orientation (hereinafter as orientation) also exhibits different inactivation performance For example for No9 conical-hole orifice plate with 39 hole-area percentage the inactivation percentage for the small-to-large orientation was 3926 which was 16599 higher than that observed for the large-to-small orientation Moreover in terms of energy efficiency the AMIJ for the small-to-large orientation was 201times107 cells∙J-1 which is only 635 higher than that exhibited by the large-to-small orientation For a single-hole orifice plate microalgae inactivation by hydrodynamic cavitation most likely occurs on its downstream side While for conical-hole orifice plate higher Heterosigma akashiwo inactivation percentage and pressure difference were observed when the conical-hole orifice plate was oriented in the small-to-large direction in which hydrodynamic cavitation only occurred on its upstream side Probably the modification in orifice plate shape changed the velocity profile around the orifice plate thus altered the occurring location of hydrodynamic cavitation while the exactly reason still deserves further investigation 34 Repeating Inactivation of Heterosigma akashiwo by Orifice Plate Repeating inactivation using orifice plates is tried to elevate the inactivation percentage Two schemes of repeating inactivation are presented here Firstly series-connection of two single-hole orifice plates with the same specification is used to inactivate Heterosigma akashiwo and the representative results are shown in Table 5 With series-connection due to the elevation in pressure difference the inactivation percentage increased while AMIJ and the flow rate decreased Eg for single-hole orifice plates each with 25 hole-area percentage after series-connection an inactivation percentage of 4929 was obtained which was 1616 higher than that of a single orifice plate alone In contrast the AMIJ decreased to 161times106cells∙J-1 which was 299 lower than that of a single one Meanwhile cycling inactivation of Heterosigma akashiwo using a conical-hole orifice plate was also performed and the results are shown in Fig6 The inactivation percentage increased with additional inactivation cycles After 4-cycle inactivation there was a 74 increase in inactivation percentage as compared to 1-cycle inactivation Additional increasing in cycle



number to 5 only elevated the inactivation percentage by 05 On the other hand after 4-cycle inactivation there was a 162times107 cells∙J-1 decline in the AMIJ which was 338 lower than that of 1-cycle inactivation 35 Energy Consumption of Heterosigma akashiwo Inactivation by Orifice

Plate-generated Hydrodynamic Cavitation The specific energy consumption under different treatment conditions with inactivation percentages around 50 (except for No2 orifice plate) were calculated and the results are shown in Table 6 The specific energy consumption of a No9 conical-hole orifice plate with small-to-large orientation was 17225 J∙m-3 which consumed only 684 energy relative to that consumed using the No3 single-hole orifice plate Ballast water passing through either a single- or multi-hole orifice plate may be regarded as experiencing treatment using a series-connection of one conical-hole orifice plate with the large-to-small orientation and subsequent another one with the small-to-large orientation Probably this is the reason why single- or multi-hole orifice plates exhibit much higher energy consumption than conical-hole one For repeating inactivation series-connection elevated the specific energy consumption drastically (See Table 4 No 5 and 9 orifice plates) which is consistent with the energy efficiency results obtained in Section 34 The results indicate that although series-connection treatment and cycling inactivation both can improve the inactivation percentage the dramatic decline in energy efficiency offsets any advantages offered by repeating inactivation The specific energy consumption for currently used type-approved ballast water management systems based on UV treatment technology and the IMO meeting standards is 431138 to 547200 J∙m-3 In comparison the specific energy consumption for conical-hole-generated hydrodynamic cavitation based on 50 inactivation was about 25 to 32 times lower than previously mentioned ballast water management systems (based on results in Table 6 No5 Conical-hole SrarrL) Due to its low specific energy consumption conical hole-generated hydrodynamic cavitation shows great potential for use in ballast water treatment 4 Conclusions Orifice plate-generated hydrodynamic cavitation was employed to inactivate viable Heterosigma akashiwo in simulated ballast water For single- and multi-hole orifice plates increases in hole-area percentage and hole-number each showed negative effects on the inactivation percentage while exhibiting positive impacts on energy efficiency In comparison with single- and multi-hole orifice plates the use of conical-hole orifice plate yielded the highest inactivation percentage of 5112 with only 684 energy consumption (based on 50 inactivation percentage) Moreover much lower pressure was needed to trigger the hydrodynamic cavitation which allowed use of a low-pressure pump Generally conical hole-generated hydrodynamic cavitation exhibits excellent performance and shows great potential as a pre-inactivation technique to treat ballast water 5 References [1] S Arrojo Y Benito A theoretical study of hydrodynamic cavitation Ultrason Sonochemistry 15 (2008) 203ndash211 [2] MV Bagal PR Gogate Degradation of diclofenac sodium using combined processes based on hydrodynamic cavitation and heterogeneous photocatalysis Ultrason Sonochemistry 21(3) (2014) 1035ndash1043



[3] B Balasundaram STL Harrison Optimising orifice geometry for selective release of periplasmic products during cell disruption by hydrodynamic cavitation Biochem Eng J 3(2011) 207ndash209 [4] N Bax A Williamson M Aguero et al Marine invasive alien species a threat to global biodiversity Mar policy 27(4) (2003) 313ndash323 [5] HA Bowers C Tomas T Tengs JW Kempton AJ Lewitus DW Oldach Raphidophyceae [Chadefaud Ex Silva] systematics and rapid identification sequence analyses and Real-Time PCR Assays J Phycol 42 (6)(2006) 1333ndash1348 [6] AG Chakinala DH Bremner PR Gogate KC Namkung AE Burgess Multivariate analysis of phenol mineralisation by combined hydrodynamic cavitation and heterogeneous advanced Fenton processing Appl Catal B-Environ 78(1-2) (2008) 11ndash18 [7] PR Gogate Application of cavitational reactors for water disinfection Current status and path forward J Environ Manage 85 (2007) 801ndash815 [8] PR Gogate Hydrodynamic cavitation for food and water processing Food Bioprocess Technol 4 (2011) 996ndash1011 [9] PR Gogate AM Kabadi A review of applications of cavitation in biochemical engineeringbiotechnology Biochem Eng J 1(2009) 60ndash72 [10] International Maritime Organization (IMO) httpwwwimoorgOurWorkEnvironment BallastWaterManagementDocumentsTable20of20BA20FA20TA20updated20in20May202014pdf lastly updated 2014519 [11] KR Murphy JR Boehme Exploring the limits of dissolved organic matter fluorescence for determining sea water sources and ballast water exchange on the US Pacific coast J Marine Syst 111ndash112 (2013) 157ndash166 [12] L Nengye M Frank The European Union and the International Maritime Organization EUs External Influence on the Prevention of Vessel-Source Pollution J Mar Law Comm 41 (2012) 581ndash594 [13] A Pal Ashish Verma SS Kachhwaha S Maji Biodiesel production through hydrodynamic cavitation and performance testing Renew Energ 35 (2010) 619ndash624 [14] PN Patil PR Gogate Degradation of methyl parathion using hydrodynamic cavitation Effect of operating parameters and intensification using additives Sep Purif Technol 95 (2012) 172ndash179 [15] E Petrucci LD Palma Biocides electrogeneration for a zero-reagent on board disinfection of ballast water J Appl Electrochem 43 (2013) 237ndash244 [16] SS Save AB Pandit JB Joshi Microbial cell disruption role of cavitation Chem Eng J Biochem Eng J 3(1994) B67ndashB72 [17] SS Sawant AC Anil K Venkat C Gaonkar J Kolwalkar L Khandeparker DV Desai AV Mahulkar VV Ranade AB Pandit Effect of hydrodynamic cavitation on zooplankton A tool for disinfection Biochem Eng J 42 (2008) 320ndash328



[18] M Sivakumar AB Pandit Wastewater treatment a novel energy efficient hydrodynamic cavitational technique Ultrason Sonochemistry 9(2002) 123ndash131 [19] SH Sonawane SP Gumfekar KH Kate SP Meshram KJ Kunte L Ramjee CM Mahajan MG Parande M Ashokkumar Hydrodynamic Cavitation-Assisted Synthesis of Nanocalcite Int J Chem Eng 2010 DOI 1011552010242963 [20] E Tsolaki E Diamadopoulos Technologies for ballast water treatment a review J Chem Technol Biotechnol 85(2010) 19ndash32 [21] N P Vichare P R Gogate A B Pandit Optimization of hydrodynamic cavitation using a model reaction Chem Eng Technol 8(23) (2000) 683ndash690 [22] B Werschkuna S Banerjia OC Basurkob et al Emerging risks from ballast water treatment The run-up to the International Ballast Water Management Convention Chemosphere 112(2014) 256ndash266 [23] ZL Wu HF Shen Removal of blue-green algae using the hybrid method of hydrodynamic cavitation and ozonation J Hazard Mater 235-236 (2012) 152ndash158 [24] NH Zhang ZT Zhang MD Bai Evaluation of the ecotoxicity and biological efficacy of ships ballast water treatment based on hydroxyl radicals technique Mar Pollut Bull 64 (2012) 2742ndash2748 [25] TY Zhao JL Zhang Experimental study of a simple pressure loss coefficient model for multi-hole orifice J Harbin Inst Tech(New Series) 15(3)(2008) 399ndash403 6 Appendix A-Calculation of the Energy Consumed Per Cubic Meter of Sea water Assuming sea water is incompressible and based on Bernoullirsquos equation total energy per unit mass of sea water ( J∙kg-1) is given by

2

2 s

u pgz

(A1)

Where u is the sea water velocity m∙s-1

1p is the pressure Pa

s is the sea water density kg∙m-3

And z is the height difference between the calculating point of the pipe and the datum

level m The energy consumed per unit mass of sea water due to hydrodynamic cavitation is given by

2 2

1 1 2 21 2( ) ( )

2 2s s

u p u pgz gz

(A2)

Where the subscripts ldquo1rdquo and ldquo2rdquo denote the position on the pipe just before and after the orifice plate respectively Assuming the pipe diameter is constant and the pipe is mounted horizontally it follows that

1 2z z 1 2u u and the following expression applies



1 2

s

p p

(A3)

Thus the energy consumption per cubic meter sea water (Ws) is

1 2

1 2s s s

s

p pW p p

(A4)

Since the pressure value obtained by pressure transducer is in PSI equation A4 is modified as

3

1 2689 10 ( )sW p p (A5)

Where and are the pipe pressures just before and after the orifice plate respectively PSI 7 Appendix B-Calculation of the Amount of Microalgae Killed Per Joule The amount of microalgae killed per cubic meter is given by

6 3

1 2 3

10( )

cmn n n

m (A6)

Therefore the amount of microalgae killed per joule (AMIJ As cells∙J-1) is

6 2

1 2 1 2

3

1 2 1 2

( ) 10 145 10 ( )

689 10 ( ) ( )s

n n n nA

p p p p

(A7)

Where

n1 and n2 are the concentrations of viable microalgae before and after treatment respectively cell∙mL-1 and are the pipe pressures just before and after the orifice plate respectively PSI

Table 1 Parameters of experimental single-and multi-hole orifice plates

No Number of holes

Hole diameter

(mm)

Total hole area percentage ()

Total hole area (mm2)

Total hole perimeter

(mm)

Cavitation number

(Cv)

1 4 8 25 20096 10053 0945

2 4 4 6 5024 5027 0098

3 1 8 6 5024 2513 0102

4 1 12 14 11304 3770 04602

5 1 16 25 20096 5027 1130

6 1 20 39 314 6283 2215

7 1 26 66 53066 8168 6006

8 16 2 6 5024 10053 0080

Note The inner pipe diameter is 32mm

1p 2p

1p 2p



Table 2 Parameters of experimental conical-hole orifice plates

No

Small-hole

diameter (mm)

Small-hole

area(mm2)

Hole area percentage

()

Large-hole

diameter (mm)

Length

(mm)

Assembling

orientation

Cavitation

number (Cv)

9 20 20096 39 32 34 LrarrS 3015

SrarrL 3225

10 16 314 25 32 45 LrarrS 1912

SrarrL 1918


Table 3 Impact of hole number on the inactivation of Heterosigma akashiwo under constant pressure difference

No Number of holes


(mm)

Microalgae inactivation

percentage ()

The amount of microalgae inactivated per joule (106 cells∙J-1)

Flow rate (m3∙h-1)

3 1 2513 4967 1444 2317

2 4 5027 3645 106 3134

8 16 10053 3056 0684 3417

Note The pressure difference before and after the orifice plate was kept constant at 216times105 Pa

Table 4 Inactivation of Heterosigma akashiwo using conical-hole orifice plates

Orifice plate

number

Assembling Orientation

Flow rate

(m3∙h-1)

Pressure before the

orifice plate (Pa)

Pressure difference before and

after the orifice plate (Pa)

Inactivation percentage

()

The amount of microalgae

inactivated per joule

(107 cells∙J-1)

9 LrarrS 3866 7579 5512 1476 189

SrarrL 3679 16536 13780 3926 201

10 LrarrS 3684 9646 7579 1867 174

SrarrL 3672 19981 17225 5112 210

Note The initial viable Heterosigma akashiwo concentration was 706times105 cells∙mL-1

Table 5 Inactivation of Heterosigma akashiwo using two series-connected single-hole orifice plates with the same specification

Orifice plate

number


Pressure difference before and after the orifice plate (105 Pa)


()


inactivated per joule (106 cells∙J-1)

5 2874 2232 4929 161

6 0394 3348 4181 761

Notes The initial viable Heterosigma akashiwo concentration was 171times106 cells∙mL-1



Table 6 The specific energy consumption for hydrodynamic cavitation under different

treatment conditions

Orifice plate number

Treatment conditions Inactivation

percentage ()

Specific energy consumption (J∙m-

3）

3 Single-hole 4924 251660

2 Multi-hole 4044 215440

5 Single hole double series-

connection treatment 4929 223207

9

Conical-hole SrarrL 5112 17225

Conical-hole SrarrL 3-cycle inactivation

5765 51690

Fig 1 Schematic of hydrodynamic cavitation setup

Fig2 Pictures of single- multi- and conical-hole orifice plate

Raw water tank

Pressure transducer 2

Orifice plate

Valve 1 Valve 2

Flow meter High pressure

centrifugal pump


Treated water tank

For circling inactivatio

n

1

3 4 5 6

7 8 2 10

9



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)

Hole-area percentage ()

0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)

Fig 3 Impact of single-hole orifice plate hole-area percentage on inactivation percentage and the amount of microalgae inactivated per joule (A) and the flow rate and pressure difference before and after the orifice plate (B) The initial viable Heterosigma akashiwo concentration was 945times105 cells∙mL-1 The increased hole-area percentages presented in X axis each correspond to No3 to No7 single-hole orifice plates



Fig 4 A typical enumeration result of Heterosigma akashiwo stained with GuavaregViacountreg by cytometry A without treatment B with hydrodynamic cavitation treatment No3 single-hole orifice plate was used Treatment condition flow rate 2685 m3∙h-1 pressure difference before and after the orifice plate 255times105 Pa and the initial viable Heterosigma akashiwo concentration was 945times105 cells∙mL-1

0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()

6 Hole-area percentage

411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage

6 Hole-area percentage (C)

0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)

Fig 5 Impact of orifice plate hole-number on inactivation percentage (A) the amount of microalgae inactivated per joule (B) pressure difference before and after the orifice plate (C) and flow rate (D) The initial viable Heterosigma akashiwo concentration was 98times105 cells∙mL-1

Dead cell and its nucleus-containing

debris 5327 count∙mL-1

Viable cell 67456

cell∙mL-1

A B

Viable cell 33215 cell∙mL-

1





1 2 3 4 50

10

20

30

40

50

60

Cycling inactivation time

Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)

Fig 6 Impact of cycling time on inactivation percentage (A) and the amount of microalgae inactivated per joule (B) A No9 conical-hole orifice plate was used with small-to-large assembling orientation Initial viable Heterosigma akashiwo concentration was 169times106 cells∙mL-1

__________

MEPC 71INF9


3 The purpose of the Guidelines for approval of ballast water management systems (G8) is to ensure uniform and proper application of the standards contained in the Convention 4 Currently filtration electrolysis and ultraviolet irradiation are the most commonly used techniques in most ballast water management systems (BWMS) However these techniques possess some disadvantages such as high energy consumption potential risk to the receiving water body etc In comparison with the traditionally used single- and multi-hole orifice plates the conical-hole orifice plate yielded the highest inactivation percentage 5112 and consumed only 684 energy (based on a 50 inactivation percentage) Moreover it allowed the use of a low-pressure pump 5 On the basis of the above Shanghai Maritime University China conducted a series of experiments to gain a new environmentally friendly technology of BWMS with economic benefit and safety as set out in the annex Action requested of the Committee 6 The Committee is invited to note the information contained in this document



ANNEX


CAVITATION









3

1 2689 10 ( )sW p p




2

1 2

1 2

145 10 ( )

( )s

n nA

p p




















2

2 s

u pgz

(A1)






2 2

1 1 2 21 2( ) ( )

2 2s s

u p u pgz gz

(A2)





1 2

s

p p

(A3)


1 2

1 2s s s

s

p pW p p

(A4)


3

1 2689 10 ( )sW p p (A5)


6 3

1 2 3

10( )

cmn n n

m (A6)


6 2

1 2 1 2

3

1 2 1 2

( ) 10 145 10 ( )

689 10 ( ) ( )s

n n n nA

p p p p

(A7)

Where



No Number of holes

Hole diameter

(mm)




(mm)

Cavitation number

(Cv)

1 4 8 25 20096 10053 0945

2 4 4 6 5024 5027 0098

3 1 8 6 5024 2513 0102

4 1 12 14 11304 3770 04602

5 1 16 25 20096 5027 1130

6 1 20 39 314 6283 2215

7 1 26 66 53066 8168 6006

8 16 2 6 5024 10053 0080


1p 2p

1p 2p




No

Small-hole

diameter (mm)

Small-hole

area(mm2)


()

Large-hole

diameter (mm)

Length

(mm)

Assembling

orientation

Cavitation

number (Cv)

9 20 20096 39 32 34 LrarrS 3015

SrarrL 3225

10 16 314 25 32 45 LrarrS 1912

SrarrL 1918



No Number of holes


(mm)


percentage ()



3 1 2513 4967 1444 2317

2 4 5027 3645 106 3134

8 16 10053 3056 0684 3417



Orifice plate

number


Flow rate

(m3∙h-1)

Pressure before the

orifice plate (Pa)




()



(107 cells∙J-1)

9 LrarrS 3866 7579 5512 1476 189

SrarrL 3679 16536 13780 3926 201

10 LrarrS 3684 9646 7579 1867 174

SrarrL 3672 19981 17225 5112 210



Orifice plate

number




()



5 2874 2232 4929 161

6 0394 3348 4181 761








percentage ()


3）


2 Multi-hole 4044 215440



9



5765 51690



Raw water tank


Orifice plate

Valve 1 Valve 2


centrifugal pump


Treated water tank


n

1

3 4 5 6

7 8 2 10

9



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)


0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)





0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________



ANNEX


CAVITATION









3

1 2689 10 ( )sW p p




2

1 2

1 2

145 10 ( )

( )s

n nA

p p




















2

2 s

u pgz

(A1)






2 2

1 1 2 21 2( ) ( )

2 2s s

u p u pgz gz

(A2)





1 2

s

p p

(A3)


1 2

1 2s s s

s

p pW p p

(A4)


3

1 2689 10 ( )sW p p (A5)


6 3

1 2 3

10( )

cmn n n

m (A6)


6 2

1 2 1 2

3

1 2 1 2

( ) 10 145 10 ( )

689 10 ( ) ( )s

n n n nA

p p p p

(A7)

Where



No Number of holes

Hole diameter

(mm)




(mm)

Cavitation number

(Cv)

1 4 8 25 20096 10053 0945

2 4 4 6 5024 5027 0098

3 1 8 6 5024 2513 0102

4 1 12 14 11304 3770 04602

5 1 16 25 20096 5027 1130

6 1 20 39 314 6283 2215

7 1 26 66 53066 8168 6006

8 16 2 6 5024 10053 0080


1p 2p

1p 2p




No

Small-hole

diameter (mm)

Small-hole

area(mm2)


()

Large-hole

diameter (mm)

Length

(mm)

Assembling

orientation

Cavitation

number (Cv)

9 20 20096 39 32 34 LrarrS 3015

SrarrL 3225

10 16 314 25 32 45 LrarrS 1912

SrarrL 1918



No Number of holes


(mm)


percentage ()



3 1 2513 4967 1444 2317

2 4 5027 3645 106 3134

8 16 10053 3056 0684 3417



Orifice plate

number


Flow rate

(m3∙h-1)

Pressure before the

orifice plate (Pa)




()



(107 cells∙J-1)

9 LrarrS 3866 7579 5512 1476 189

SrarrL 3679 16536 13780 3926 201

10 LrarrS 3684 9646 7579 1867 174

SrarrL 3672 19981 17225 5112 210



Orifice plate

number




()



5 2874 2232 4929 161

6 0394 3348 4181 761








percentage ()


3）


2 Multi-hole 4044 215440



9



5765 51690



Raw water tank


Orifice plate

Valve 1 Valve 2


centrifugal pump


Treated water tank


n

1

3 4 5 6

7 8 2 10

9



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)


0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)





0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________







3

1 2689 10 ( )sW p p




2

1 2

1 2

145 10 ( )

( )s

n nA

p p




















2

2 s

u pgz

(A1)






2 2

1 1 2 21 2( ) ( )

2 2s s

u p u pgz gz

(A2)





1 2

s

p p

(A3)


1 2

1 2s s s

s

p pW p p

(A4)


3

1 2689 10 ( )sW p p (A5)


6 3

1 2 3

10( )

cmn n n

m (A6)


6 2

1 2 1 2

3

1 2 1 2

( ) 10 145 10 ( )

689 10 ( ) ( )s

n n n nA

p p p p

(A7)

Where



No Number of holes

Hole diameter

(mm)




(mm)

Cavitation number

(Cv)

1 4 8 25 20096 10053 0945

2 4 4 6 5024 5027 0098

3 1 8 6 5024 2513 0102

4 1 12 14 11304 3770 04602

5 1 16 25 20096 5027 1130

6 1 20 39 314 6283 2215

7 1 26 66 53066 8168 6006

8 16 2 6 5024 10053 0080


1p 2p

1p 2p




No

Small-hole

diameter (mm)

Small-hole

area(mm2)


()

Large-hole

diameter (mm)

Length

(mm)

Assembling

orientation

Cavitation

number (Cv)

9 20 20096 39 32 34 LrarrS 3015

SrarrL 3225

10 16 314 25 32 45 LrarrS 1912

SrarrL 1918



No Number of holes


(mm)


percentage ()



3 1 2513 4967 1444 2317

2 4 5027 3645 106 3134

8 16 10053 3056 0684 3417



Orifice plate

number


Flow rate

(m3∙h-1)

Pressure before the

orifice plate (Pa)




()



(107 cells∙J-1)

9 LrarrS 3866 7579 5512 1476 189

SrarrL 3679 16536 13780 3926 201

10 LrarrS 3684 9646 7579 1867 174

SrarrL 3672 19981 17225 5112 210



Orifice plate

number




()



5 2874 2232 4929 161

6 0394 3348 4181 761








percentage ()


3）


2 Multi-hole 4044 215440



9



5765 51690



Raw water tank


Orifice plate

Valve 1 Valve 2


centrifugal pump


Treated water tank


n

1

3 4 5 6

7 8 2 10

9



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)


0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)





0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________

















2

2 s

u pgz

(A1)






2 2

1 1 2 21 2( ) ( )

2 2s s

u p u pgz gz

(A2)





1 2

s

p p

(A3)


1 2

1 2s s s

s

p pW p p

(A4)


3

1 2689 10 ( )sW p p (A5)


6 3

1 2 3

10( )

cmn n n

m (A6)


6 2

1 2 1 2

3

1 2 1 2

( ) 10 145 10 ( )

689 10 ( ) ( )s

n n n nA

p p p p

(A7)

Where



No Number of holes

Hole diameter

(mm)




(mm)

Cavitation number

(Cv)

1 4 8 25 20096 10053 0945

2 4 4 6 5024 5027 0098

3 1 8 6 5024 2513 0102

4 1 12 14 11304 3770 04602

5 1 16 25 20096 5027 1130

6 1 20 39 314 6283 2215

7 1 26 66 53066 8168 6006

8 16 2 6 5024 10053 0080


1p 2p

1p 2p




No

Small-hole

diameter (mm)

Small-hole

area(mm2)


()

Large-hole

diameter (mm)

Length

(mm)

Assembling

orientation

Cavitation

number (Cv)

9 20 20096 39 32 34 LrarrS 3015

SrarrL 3225

10 16 314 25 32 45 LrarrS 1912

SrarrL 1918



No Number of holes


(mm)


percentage ()



3 1 2513 4967 1444 2317

2 4 5027 3645 106 3134

8 16 10053 3056 0684 3417



Orifice plate

number


Flow rate

(m3∙h-1)

Pressure before the

orifice plate (Pa)




()



(107 cells∙J-1)

9 LrarrS 3866 7579 5512 1476 189

SrarrL 3679 16536 13780 3926 201

10 LrarrS 3684 9646 7579 1867 174

SrarrL 3672 19981 17225 5112 210



Orifice plate

number




()



5 2874 2232 4929 161

6 0394 3348 4181 761








percentage ()


3）


2 Multi-hole 4044 215440



9



5765 51690



Raw water tank


Orifice plate

Valve 1 Valve 2


centrifugal pump


Treated water tank


n

1

3 4 5 6

7 8 2 10

9



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)


0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)





0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________



1 2

s

p p

(A3)


1 2

1 2s s s

s

p pW p p

(A4)


3

1 2689 10 ( )sW p p (A5)


6 3

1 2 3

10( )

cmn n n

m (A6)


6 2

1 2 1 2

3

1 2 1 2

( ) 10 145 10 ( )

689 10 ( ) ( )s

n n n nA

p p p p

(A7)

Where



No Number of holes

Hole diameter

(mm)




(mm)

Cavitation number

(Cv)

1 4 8 25 20096 10053 0945

2 4 4 6 5024 5027 0098

3 1 8 6 5024 2513 0102

4 1 12 14 11304 3770 04602

5 1 16 25 20096 5027 1130

6 1 20 39 314 6283 2215

7 1 26 66 53066 8168 6006

8 16 2 6 5024 10053 0080


1p 2p

1p 2p




No

Small-hole

diameter (mm)

Small-hole

area(mm2)


()

Large-hole

diameter (mm)

Length

(mm)

Assembling

orientation

Cavitation

number (Cv)

9 20 20096 39 32 34 LrarrS 3015

SrarrL 3225

10 16 314 25 32 45 LrarrS 1912

SrarrL 1918



No Number of holes


(mm)


percentage ()



3 1 2513 4967 1444 2317

2 4 5027 3645 106 3134

8 16 10053 3056 0684 3417



Orifice plate

number


Flow rate

(m3∙h-1)

Pressure before the

orifice plate (Pa)




()



(107 cells∙J-1)

9 LrarrS 3866 7579 5512 1476 189

SrarrL 3679 16536 13780 3926 201

10 LrarrS 3684 9646 7579 1867 174

SrarrL 3672 19981 17225 5112 210



Orifice plate

number




()



5 2874 2232 4929 161

6 0394 3348 4181 761








percentage ()


3）


2 Multi-hole 4044 215440



9



5765 51690



Raw water tank


Orifice plate

Valve 1 Valve 2


centrifugal pump


Treated water tank


n

1

3 4 5 6

7 8 2 10

9



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)


0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)





0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________




No

Small-hole

diameter (mm)

Small-hole

area(mm2)


()

Large-hole

diameter (mm)

Length

(mm)

Assembling

orientation

Cavitation

number (Cv)

9 20 20096 39 32 34 LrarrS 3015

SrarrL 3225

10 16 314 25 32 45 LrarrS 1912

SrarrL 1918



No Number of holes


(mm)


percentage ()



3 1 2513 4967 1444 2317

2 4 5027 3645 106 3134

8 16 10053 3056 0684 3417



Orifice plate

number


Flow rate

(m3∙h-1)

Pressure before the

orifice plate (Pa)




()



(107 cells∙J-1)

9 LrarrS 3866 7579 5512 1476 189

SrarrL 3679 16536 13780 3926 201

10 LrarrS 3684 9646 7579 1867 174

SrarrL 3672 19981 17225 5112 210



Orifice plate

number




()



5 2874 2232 4929 161

6 0394 3348 4181 761








percentage ()


3）


2 Multi-hole 4044 215440



9



5765 51690



Raw water tank


Orifice plate

Valve 1 Valve 2


centrifugal pump


Treated water tank


n

1

3 4 5 6

7 8 2 10

9



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)


0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)





0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________







percentage ()


3）


2 Multi-hole 4044 215440



9



5765 51690



Raw water tank


Orifice plate

Valve 1 Valve 2


centrifugal pump


Treated water tank


n

1

3 4 5 6

7 8 2 10

9



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)


0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)





0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________



0 10 20 30 40 50 60 70

24

30

36

42

48

54In

acti

vat

ion p

erce

nta

ge (

)


0

3

6

9

12

15T

he a

mount o

f micro

algae in

activ

ated

per jo

ule (1

06

cellJ

-1)

(A)

0 10 20 30 40 50 60 7000

05

10

15

20

25

Pre

ssu

re d

iffe

ren

ce b

efore

an

d

afte

r th

e ori

fice

pla

te (

10

5 P

a)


27

30

33

36

39

Flo

w rate (m

3h

-1)

(B)





0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________




0

10

20

30

40

50

60

25 Hole-area

percentage

Inac

tiv

atio

n p

erce

nta

ge

()


411641

(A)

Hole-number

0

2

4

6

8

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(10

6 c

ount

J-1)

411641

25 Hole-area

percentage


Hole-number

(B)

Pre

ssure

dif

fere

nce

bef

ore

and

afte

r ori

fice

pla

te (

10

5 P

a)

00

05

10

15

20

25

411641

Hole-number

25 Hole-area

percentage


0

1

2

3

4

Flo

w r

ate

(m3h

-1)

411641

25 Hole-area

percentage


Hole-number

(D)




Viable cell 67456

cell∙mL-1

A B


1





1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________



1 2 3 4 50

10

20

30

40

50

60


Inac

tiv

atio

n p

erce

nta

ge

()

(A)

1 2 3 4 500

04

08

12

16

20

The

amount

of

mic

roal

gae

inac

tivat

ed

per

joule

(1

07 c

ell

J-1)


(B)


__________

MARINE ENVIRONMENT PROTECTION MEPC 71/INF.9 … · the IMO (Nengye & Frank 2012). Hydrodynamic...

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Transcript of MARINE ENVIRONMENT PROTECTION MEPC 71/INF.9 … · the IMO (Nengye & Frank 2012). Hydrodynamic...